First Invention
With the rapid progress of computer techniques, disc-shaped recording media have been used widely as means for recording, reproducing, and erasing various information. With respect to disc-shaped recording media, there are a plurality of standards that differ in recording density, size, recording and reproducing system, and the like respectively. Corresponding to the respective disc-shaped recording media according to the plurality of standards, there are also a plurality of drive units for recording information on and reproducing and erasing information from the respective disc-shaped recording media.
Under such circumstances, it is convenient for users when disc-shaped recording media according to a plurality of standards can be driven for recording, reproducing, and erasing information with one drive unit. Therefore, various systems have been proposed.
As a method for driving a plurality of disc-shaped recording media having different sizes for recording, reproducing, and erasing information with one drive unit, for example, a method in which a user inserts a bare disc-shaped recording medium into an adapter and then sets it into a drive unit has been proposed. Partially, this method has come into practical use for driving both a compact disc (CD) with a diameter of 12 cm and a single compact disc with a diameter of 8 cm.
As a method of recording information on and reproducing and erasing information from disc-shaped recording media with various sizes accommodated in cartridges with one drive unit, for example, as shown in FIG. 51, a method of recording, reproducing, and erasing information in a drive unit 1921 designed for a large disk cartridge by inserting a small-size disk cartridge 1901 into a cartridge adapter 1911 having the same size and the same external shape as those of the large disk cartridge has been studied (for instance, Publication of Japanese Unexamined Patent Application Hei 2-121174). In FIG. 51, numerals 1912 and 1913 indicate a head access opening and a shutter of the cartridge adapter 1911, respectively. The head access opening 1912 and the shutter 1913 are formed so as to have the same shapes and sizes as those of the cartridge for a large disc. Numerals 1902 and 1903 indicate a head access opening and a shutter of the small disk cartridge 1901, respectively. A numeral 1914 indicates an insertion portion into which the small disk cartridge 1901 is inserted, and a numeral 1924 indicates an insertion portion into which the large disk cartridge is inserted.
However, the method in which a user inserts a bare disc-shaped recording medium into an adapter and sets it into a drive unit is not suitable for the use that requires high reliability and high durability, since the user can put dirt and scratches on the disc-shaped recording medium easily.
Further, in the method of recording, reproducing, and erasing information in a drive unit designed for a large disk cartridge by inserting a small disk cartridge into a cartridge adapter having the same size and the same external shape as those of the large disk cartridge as shown in FIG. 51, for example, the following problems occur. The small disk cartridge is different from the large cartridge in shapes and sizes of the head access opening and the shutter that are provided in a disk cartridge, and in the opening/closing mechanisms of the shutter. Therefore, some problems occur, for example, a head of the drive unit comes into contact with the shutter 1903 and the exterior members around the head access opening 1902 of the small disk cartridge 1901 accommodated in the cartridge adapter 1911, and the mechanism for opening and closing the shutter is complicated. As a result, in disk cartridges with different sizes, it is difficult to record, reproduce, and erase information without any problems using such an adapter. Considering such use, it has been necessary to review the design of the drive unit itself in some cases.
Second Invention
Recently, disk drive units for optical disks or the like used as recording units of computers have been required to be smaller and thinner, as portable computers have become widespread. At the same time, disks for recording and reproduction have become smaller, and therefore the disks with high recording-density have been required. Such a disk is accommodated in a cartridge case so that fingerprints and dust, which are obstacles for recording and reproducing information at a high density, do not adhere to the disk.
An example of a conventional double-sided disk cartridge and a mechanism of opening and closing its shutter will be explained with reference to the drawings as follows.
FIG. 61 is a perspective structural view of a disk cartridge in conformity with the International Standard for a 130-mm optical disk. FIG. 62 is a perspective view showing a state in which a shutter of the disk cartridge shown in FIG. 61 is opened. FIG. 63 is a partially enlarged perspective view showing a configuration around the shutter of the disk cartridge shown in FIG. 61. In this conventional disk cartridge, an optical disk 2104 is accommodated in a case body 2103 having a substantially rectangular shape formed of an upper half 2101 and a lower half 2102. An opening 2105 into which a disk motor and an optical pickup can be inserted is provided in the upper and lower surfaces of the case body 2103. A U-shaped shutter 2106 for covering and uncovering the opening 2105 is slidably provided on the case body 2103. The shutter 2106 is formed in a manner such that a metal plate is folded in two. The shutter 2106 comprises two opposed shielding plates 2107 and a connecting plate 2108 interconnecting the two opposed shielding plates. The connecting plate 2108 fixes and holds a thin and long slider 2109 so as to cover the slider 2109. A receiving hole 2110 into which a shutter opener P1 is inserted is provided to a tail portion of the connecting plate 2108. The shutter opener P1 is provided in a loading mechanism of a recording and reproducing unit. Corresponding to the receiving hole 2110, a receiving hole 2111 is provided in the slider 2109. A roller R1 of the shutter opener P1 shown in FIG. 63 is engaged with the receiving hole 2111. Atorsion coil spring 2114 is housed in the left side of the leading end of the case body 2103. This torsion coil spring 2114 urges the shutter 2106 in the direction in which the shutter 2106 covers the opening 2105.
At an end of the slider 2109, a slope 2115 is provided so that a roller R2 of a shutter opener P2 provided in the loading mechanism of the recording and reproducing unit as shown in FIG. 63 can pass over the slope 2115 smoothly.
When this conventional disk cartridge is inserted into the recording and reproducing unit, one shutter opener P1 is inserted into the receiving hole 2110 of the shutter 2106 and the receiving hole 2111 of the slider 2109. When the shutter opener P1 moves the shutter 2106 to the left to uncover the opening 2105 as shown in FIG. 62, the other shutter opener P2 crosses over and along the slope 2115 of the slider 2109. As a result, the shutter openers P1 and P2 cross each other.
Guide grooves 2116 for preventing erroneous insertion of a cartridge are formed at the leading ends of both side faces of the case body 2103. When the disk cartridge is inserted into a unit normally, auto-loading hooks (not shown in the figures) that are a loading means of the recording and reproducing unit are inserted into the guide grooves 2116, thus pulling the disk cartridge into the unit. On the other hand, when the disk cartridge is inserted into the recording and reproducing unit from its back, the auto-loading hooks come into contact with the back corners of the case body 2103. Therefore, the disk cartridge cannot be inserted any further, thus preventing the erroneous insertion. Consequently, damage to an optical head that is an information writing and reading means of the recording and reproducing unit and other mechanisms can be avoided.
At the rear of the both side faces of the case body 2103, grooves 2117 for engaging with a chucking (cramping) mechanism (not show in the figures) of a changer unit are formed. As widely known, one of a plurality of disk cartridges accommodated in a changer unit is selected and the chucking mechanism engages with grooves 2117 of the selected disk cartridge to hold and load it, thus enabling automatic selection and automatic recording/reproduction.
However, there have been the following problems in the double-sided disk cartridge having the above-mentioned conventional structure.
During the operation of opening and closing a shutter, the rollers at the ends of two shutter openers cross each other on the connecting plate 2108. Therefore, when a space is provided in order to avoid the contact between the two rollers, it is necessary to increase the thickness of the cartridge, which, as a result, goes against the trend to a thinner unit. Further, in order to obtain a thin unit, there is a cartridge in which the front-end center of the case body 2103 is formed of a bridge portion that is recessed from the two case faces so as to allow an optical head (not shown in the figure) of the unit and a cramp mechanism (not shown in the figure) for the disk to pass through. However, since such a bridge portion is further thinner than the cartridge, the rollers of the shutter openers cannot come into contact with the thinner bridge portion. Even if the rollers can come into contact with the bridge portion, the rollers are in contact with the bridge portion merely slightly. Consequently, in view of reliability, it has been difficult to apply such a cartridge to the double-sided disk cartridge.
Next, a conventional disk cartridge has a configuration in which one of the shutter openers (the shutter opener P2 in FIG. 63) shifts from the front end of the case body 2103 to the connecting plate 2108 of the shutter 2106. In the conventional disk cartridge, consideration is given to a smooth shift by providing the slope 2115 to the slider 2109. However, there has been a problem in that design errors and the like cause difference in level and therefore shift load resistance increases during the shift, resulting in bad operational feeling.
Since guide grooves 2116 for preventing erroneous insertion are provided at the leading ends of the both side faces of the case body, the space inside the case body becomes smaller. Therefore, the space in which the torsion coil spring 2114 that provides force to the shutter 2106 is moved and the moving distance of the slider 2109 are smaller and shorter than those in the case where no guide groove 2116 is provided. On the other hand, when the space required for the movement of the torsion coil spring 2114 is provided, the disk cartridge becomes bigger. Thus, it is not suitable for obtaining a smaller disk cartridge.
Further, since grooves 2117 for a changer unit are provided at the rear of the both side faces of the case body 2103, there is a possibility of damaging the peripheral surface of the disk 2104 through the contact with edges of the grooves 2117 during ejection of the disk 2104, when the disk 2104 is applied to a cartridge in which the disk 2104 is ejected from the back of the case body 2103. In order to avoid this, it is necessary to make the disk cartridge bigger so as to have an extra space at least for the grooves 2117, resulting in a bigger disk cartridge.
Thus, the configuration of the conventional double-sided disk cartridge does not enable the disk cartridge to be smaller and thinner. Therefore, there has been a problem in that it is difficult to obtain a smaller drive unit.
Third Invention
Recently, in view of large recording capacity, excellence in information search, easy handling, and the like, disks of disc-shaped recording media and disk recording and reproducing units that drive the disks have received much attention.
Such a disk is accommodated in a cartridge with a shutter so that the cartridge prevents a recording surface of the disk from being damaged or from being touched easily and keeps the recording surface away from dirt.
A configuration of a conventional disk cartridge will be explained with reference to the drawing as follows.
FIG. 68 shows plan views showing a structure of a conventional disk cartridge. FIG. 68(A) and (B) show the conventional disk cartridge with its shutter being closed and being opened, respectively.
In FIG. 68, a numeral 3101 indicates a cartridge body, which is made of synthetic resin. The cartridge body 3101 accommodates a disk 3103 of a recording medium rotatably. A numeral 3101a indicates an opening provided on both sides of the cartridge body 3101. The openings 3101a are used for exposing surfaces of the disk 3103 so that light can be irradiated onto the disk 3103 across its inner and outer peripheries for recording and reproduction. The cartridge body 3101 shown in FIG. 68 is provided so that a center hole is completely exposed through the openings 3101a, since it is necessary that a disk recording and reproducing unit holds the center hole to rotate the disk 3103. A numeral 3102 indicates a shutter that is formed of a thin plate made of metal such as aluminum, or a synthetic resin plate. The shutter 3102 is maintained by the cartridge body 3101 slidably so as to cover the openings 3101a completely to shield the disk 3103 or so as to uncover the openings 3101a to expose the disk 3103.
The operation of such a conventional disk cartridge will be explained.
When the cartridge body 3101 having the shutter 3102 is loaded in a disk recording and reproducing unit, a concave part 3102a provided in the shutter 3102 engages with an opener lever OL of the disk recording and reproducing unit as shown in FIG. 68(A) and the shutter 3102 slides to the right (in the direction indicated with an arrow O in FIG. 68). Thus, the openings 3101a are uncovered. On the other hand, when the cartridge body 3101 is drawn out from the recording and reproducing unit, the shutter 3102 slides to the left (in the direction indicated with an arrow S in FIG. 68) by a shutter return spring 3104 inside the cartridge as shown in FIG. 68(B) to return to the initial position. Thus, the shutter covers the openings 3101a and thus the disk surfaces are not exposed. The cartridge body 3101 has the above-mentioned configuration.
As shown in FIG. 68(B), the conventional disk cartridge had a configuration in which the shutter 3102 that has been moved to the side is not positioned outside the cartridge body 3101 beyond its peripheral end when the shutter 3102 is opened to expose the openings 3101a completely.
That is to say, as shown in FIG. 70, the conventional disk cartridge had a configuration in which L3=L2&gt;L1.gtoreq.L0 is satisfied, wherein with a closed shutter, L represents the width of the disk cartridge (cartridge body) in the sliding direction of the shutter, L0 represents the width of the opening, L1 is the width of the shutter, L2 is the distance between the leading end of the shutter in its sliding direction and the peripheral end of the cartridge body that is nearer to the above-mentioned leading end (the width of a region where the shutter is positioned when being moved to the side), and L3 represents the distance between the rear end of the shutter in its sliding direction and the peripheral end of the cartridge body that is nearer to the above-mentioned rear end (generally L3=L2). In this case, the width L of the whole cartridge had to be set to satisfy L3+L1+L2&gt;3.times.L1 inevitably.
However, in the above-mentioned conventional disk cartridge, when the openings 3101a become larger, the shutter 3102 covering the openings 3101a also becomes larger. At the same time, the required space for positioning the shutter when the shutter is moved to the side becomes larger. Consequently, there has been a problem in that the cartridge itself comes to have a large size.
Especially, as shown in FIG. 69, in a disk cartridge for a small-diameter disk 3003 in which only its capacity is reduced by decreasing the disk diameter without changing its recording and reproducing system and drive system and in which its small size, light weight, and portability are considered as important, the size of an opening 3111a, especially its width in the sliding direction is fixed. Therefore, the width of a shutter 3112 and the width of the region where the shutter 3112 is positioned when being moved to the side are increased. As a result, only the cartridge size is larger than needed for the small-diameter disk 3003, which has been a disadvantage.